Canopy bubbles allow for visibility

An improved version of the P-51 Mustang, the D-model, had upgraded weaponry and a single-piece bubble canopy. Making a large canopy with virtually no visual distortion and hardly any support structure was a bit of a challenge. But the most modern fighters had bubbles in order to allow a pilot much better visibility, particularly behind the airplane, where a threat would most likely come from. Some flyers, especially those based in the Pacific, complained that the new canopies acted like a giant magnifying glass, slowly cooking their noggin. They griped that flying under the plastic for hours and hours was like sitting in a giant rotisserie!